Find the directional derivative of f(x,y,z)=x2+y2+z2f(x, y, z) = x^2 + y^2 + z^2f(x,y,z)=x2+y2+z2 at (1,1,1)(1, 1, 1)(1,1,1) in the direction of the vector v=⟨1,1,0⟩\mathbf{v} = \langle 1, 1, 0 \ranglev=⟨1,1,0⟩.
2\sqrt{2}2
222\sqrt{2}22
222
22\frac{2}{\sqrt{2}}22